opencascade: New formula

opencascade.org (3D modeling & numerical simulation)

Closes #624.
oce: New formula

OpenCascade Community Edition

Closes #629.
bedtools 2.19.0

Closes #669.
mathgl: 2.2.1

This new version fixes the build with recent gsl versions.
Conditionally enable OpenMP.
Streamline build options.

Closes #588. Closes #661.
insighttoolkit: Disable python wrappings

Added message that python binaries can be found in a private tap.

Closes #649.
ann: Fix compilation in mavericks

Closes #425.